(1) Field of the Invention
This invention relates to heaters that can be used in a conventional fireplace to provide more efficient use of the heat energy released therein.
(2) Description of the Prior Art
Prior art devices have used a number of different heat exchangers. See for example U.S. Pat. Nos. 4,008,707, 3,930,490 and 4,019,492.
In U.S. Pat. No. 3,930,490, a heater is disclosed having vertical and horizontal tubes running around the sides and over the top of the fire supporting grate.
In U.S. Pat. No. 4,008,707, a removable heater is disclosed having large hollow wall sections adapted to fit the interior of a fireplace. The hollow sections have corrugated inner walls for increased heat transfer.
U.S. Pat. No. 4,019,492 shows an automatic furnace which uses a number of horizontally disposed pipes above and behind the combustion area. Combustion air is supplied by a perforated air delivery tube which appears to be the novelty in the disclosure.
Applicant's device uses a number of semi-U shaped horizontal tubes in vertically spaced relation to one another that conform generally to the shape of the inner back and side walls of a conventional fireplace.